Froth flotation concentration of sylvite from sylvinite ores



Patented Mar. 11, 1952 FROTH FLO'TATION CONCENTRATION OF SYLVITE FROM SYLVINITE ORES Arthur J. Weinig, Golden, 0010., assignor to Potash Company of America, a corporation of Colorado No Drawing. Application April 16, 1948,

Serial No. 21,541

4 Claims. (Cl. 209-166) This invention relates to the froth flotation treatment of potash-bearing ores such as the sylvinite ores of the Carlsbad, New Mexico, deposit, and is a continuation in part of my application Serial No. 582,573, now abandoned.

While it was only recently discovered that the soluble constituents of sylvinite ore could be separated by froth flotation, many processes have been devised for so treating these ores. Thus, in my Patent No. 2,188,932, I have disclosed a milling circuit and suitable reagents for concentrating the sylvite or KCl content by floating the sylvite, while in my Patent No. 2,211,397 I have disclosed another milling circuit involving What is termed upside-down flotation, with the sylvite collected as a purified residue or concentrate' of the flotation separation. The operation disclosed in the latter patent has been used commercially for a number of years with highly eihcient results.

However, such an operation is best suited for treatment of ores having a KCl content of 40% or higher, as then only a fair proportion of the total weight of the ore treated is required to be floated in attaining the desired separation. As the deposits are worked to a greater extent, the ore having a high KCl content is depleted, requiring treatment of ore having a lesser KCl content, and in treating ores of the latter type it is advantageous to float the KCl because of the smaller tonnage of concentrate to be obtained from a given quantity of ore. I It is an object of the present invention to provide a simple, economical and efiicient froth flotation separation of the soluble constituents of sylvinite ores.

Another object of this invention is to provide a group of collector reagents which are adapted to induce a selective flotation of the sylvite constituents of sylvinite ores.

A further object of the invention is to provide a novel flotation procedure for concentrating the sylvite content of sylvinite ores.

Other objects reside in novel steps and treatments, all of which will appear more fully in the course of the following description. M invention in brief resides in the discovery that chlorinated aminated aliphatic hydrocarbon mixtures approximating kerosene in appearance and general properties are Well suited for use as collector reagents when the sylvinite ore contains some dissolved lead or bismuth salts. I

In preparing my collector reagent a crude oil,

preferably such as that obtained from Mt.

Pleasant, Michigan, is selected to obtain a relatively unsaturated kerosene by known distillation processes, this kerosene being reacted subsequently in known manner with ammonia and chlorine and compounds thereof to yield a final oil-like reagent containing from 0.90-29.0% chlorine and 5.0-14.0% nitrogen when properly processed as hereinafter described. The final product is an oily liquid, mildly alkaline in nature and apparently containing a large proportion of primary aliphatic amines.

The reagent is introduced into said pulp and being a liquid distributes readily. Preferably, the amount of reagent used will be from A to 10 lbs. per ton of ore treated. By recycling the solution, whatever excess of reagent remains in the brine will be available in the next cycle of operation and remains active throughout a'succession of such treatments.

The froth produced by these reagents is different than froths produced by the other collector reagents heretofore used in such treatments in that it is very brittle and quick-breaking with consequent benefits to subsequent plant operations. Under the action of the reagent, the sylvite content concentrates in the froth, while the halite and gangue constituents are inert to the action of the reagent and pass from the treatment as the tailings of the operation.

The results of a typical, simple flotation treatment follow to demonstrate the effectiveness of Per Per Cent Weight Rougher froth (unclcaned) 49. 8 80.0 Rougher tail 51. 1 0.3 Heads 100.0 40. 2 Recovery.-. 99. 8

Reagent use: 1% lbs. Dak, per ton of head ore.

1 For commercial operations, it will be desirable to employ secondary heat and precipitation treatments in order to avoid undue sliming in grinding and to obtain maximum recovery. A circuit'well suited for such purposes has been shown and described in my Patent No. 2,188,932, and in such a circuit the present reagents will be present at the respective flotation stages and will produce the sylvite concentration as hereinbefore described.

However, in order to demonstrate the advantages of the secondary treatments, the aforesaid treatment was repeated in all respects and the rougher froth was refloated or cleaned in the same brine used for the roughing test, but without further reagent introduction. Next, the cleaner tail was heated in its brine to 120 F., filtered, and the warm brine added to the cleaned flotation concentrate, and finally the whole lot was cooled to 72 F., the initial temperature of the test. The final concentrate thus was a combination of the cleaner flotation concentrate and precipitated KCl from the heat treatment of the cleaner tails. The results follow:

The oil-like reagent, designated Dak, may be prepared from a kerosene, preferably somewhat unsaturated, such as that obtained from Mt. e

Pleasant, Michigan, crudes. The kerosene may be chlorinated by conventional methods and aminated in a solvent under elevated temperature and pressure. After amination, the amino bodies are separated from nonamino bodies by treatment with mineral acid.

The product, which contains twelve carbon aliphatic chain compounds, is distilled until the molecular weight as determined by the freezing point method reaches about 240, although other weights from 190 to 260 may be employed if desired. The temperature required to obtain an average molecular weight of about 240 is somewhat variable but may reach 190 at mm. of mercury pressure.

It must be understood that this product is a highly complex mixture of many compounds, incapable of precise definition or analysis and that molecular weights herein indicated are, therefore, to be considered as averages for the mixture, rather than the molecular weight of a specific compound.

When tested by Podbieniac fractionation at 2 mm. pressure, the following results were ob- The efiiciency of the various fractions obtained in the foregoing test as collector reagents is somewhat variable, but in general those having the lower boiling points are the most efficient. For example, the fraction obtained at 66 C. in the foregoing test proved to be particularly emcient. From this it may be seen that a relatively low chlorine content, as for example 0.9 to 8% chlorine is desirable as is a relatively high content of relatively short chain aliphatic carbon compounds. It also appears probable that the chlorine in the compound is combined in some peculiar way with the nitrogen containing group to yield the actually effective surface action characteristics of the liquid. The iodine value of the final product should be about '70, and the liquid mildly alkaline, requiring about 0.2 part HCl for neutralization, which permits reaction of the compound with acids, such as acetic or hydrochloric, if desired. There are probably primary, secondary, and tertiary amines present, although the primary amines appear to be predominate and may be either straight or branch chain types, or mixtures thereof, the former preferably predominating. The above described reagent differs from conventional amine reagents, however, in that it is inoperative as a flotation reagent for sylvinite ores in the absence of lead or bismuth ions in the brine.

From the foregoing it will be seen that these reagents produce a highly efiicient separation, and due to their liquid character, are very convenient to use in such treatments, particularly when the brine is recycled in the treatment. The reagent consumption is low and since the reagents are derived from hydrocarbons, the operation is quite economical.

While I prefer to use reagents of this class that are formed as liquids, it is possible to use other members of the class that are in solid form. For example, another composition of the same manufacturer essentially the residue from the above described distillation and designated Rak is a brown, brittle, resinous solid containing 5% nitrogen and 14% chlorine and has a specific gravity of 1.10. It is soluble in water to only about 5% and therefore results in much pulp dilution in feeding. Tests with this reagent show definite KCl flotation in a lead-bearing brine as previously described.

It will be understood from the foregoing that the disclosed details are given by way of illustration, rather than limitation, and that I do not therefore limit myself to these details except insofar as defined in the appended claims.

I claim:

1. A process for treating potash ores which comprises the introduction of such an ore in finely divided condition into a brine saturated with respect to the soluble ore constituents to form a pulp, introducing into the pulp ion of a metal selected from a group consisting of lead and bismuth, subjecting such pulp to a froth flotation treatment in the presence of a chlorinated aminated hydrocarbon having a molecular weight when tested by the freezing point method of between and 260 and collecting potash salts from the froth.

2. A process for treating potash ore which comprises the introduction of such an ore in flnely divided condition into a brine saturated with respect to the soluble ore constituents to form a pulp, introducing into the pulp ions of a metal selected from a group consisting of lead and bismuth, subjecting such pulp to a froth flotation treatment in the presence of a chlorinated aminated hydrocarbon having a molecular weight when tested by the freezing point method of about 240 and collecting potash salts from the froth.

3. A process for treating sylvinite ore which comprises the introduction of such an ore in finely treatment in the presence of a chlorinated aminated mixture of liquid hydrocarbon having an apparent molecular weight when tested by the freezing point method of between about 190-260 and containing from about 0.90-29.0% chlorine and 50-14% nitrogen and collecting potash salts from the froth.

4. A process for treating potash or which comprises the introduction of such an ore in finely divided condition into a brine saturated with respect to the soluble ore constituents to form a pulp, introducing into the pulp ions of a metal selected from a group consisting of lead and hismuth, subjecting such pulp to a froth flotation treatment in the presence of a chlorinated ami- 20 6 nated mixture of hydrocarbons having a molecular weight when tested by the freezing point method of between about 190-260 and containing from about 0.90-8% chlorine and collecting potash salts from the froth.

ARTHUR J. WEINIG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,088,325 Kirby July 27, 1937 2,188,932 Weinig Feb. 6, 1940 2,211,397 Weinig Aug. 13, 1940 2,238,439 Bishop Apr. 15, 1941 2,305,830 Profit Dec. 22, 1942 2,330,158 Tartaron Sept. 21, 1943 2,361,457 Clark Oct. 31, 1944 

1. A PROCESS FOR TREATING POTASH ORES WHICH COMPRISES THE INTRODUCTION OF SUCH ANORE IN FINELY DIVIDED CONDITION INTO A BRINE SATURATED WITH RESPECT TO THE SOLUBLE ORE CONSTITUENTS TO FORM A PULP, INTRODUCING INTO THE PULP IONS OF A METAL SELECTED FROM THE GROUP CONSITING OF LEAD AND BISMUTH, SUBJECTING SUCH PULP TO A FROTH FLOTATION TREATMENT IN THE PRESENCE OF A CHLORINATED AMINATED HYDROCARBON HAVING A MOLECULAR WEIGHT WHEN TESTED BY THE FREEZING POINT METHOD OF BETWEEN 190 AND 260 AND COLLECTING POTASH SALTS FROM THE FROTH. 